Months later, Trump Jr. acknowledged in a statement before the Senate Judiciary Committee in September that he met with Veselnitskaya to discuss the "fitness" of Clinton as a presidential candidate.

Trump Jr.'s appearance before the intelligence panel is his third interview on Capitol Hill, coming just one week after he voluntarily met with the House Intelligence Committee and similarly answered lawmakers' questions about his Russian contacts.

Rep. Adam Schiff (D-Calif.) last week expressed concern after Trump Jr. declined to tell the House panel details about his conversation with his father regarding his meeting with a Russian lawyer, citing client privilege.

The Democratic lawmaker argued that Trump Jr. cannot apply attorney-client privilege and "shield" lawmakers from his conversation between father and son just because an attorney was present in the room at the time.